wifi: iwlwifi: fix the rf step and flavor bits range

The macros used to get the RF step and flavour are using
wrong bit range. Update the bit range for both macros.

Signed-off-by: Mukesh Sisodiya <mukesh.sisodiya@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20231004123422.cfd0aaaa5eb3.Ie2dd6c3a3062647f19cb5e888c46f0fdca103484@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>